This invention relates to an exhaust gas muffler, which does not lower the output of an engine to which it is connected and which can arrest high frequency components of exhaust sounds.
Uncomfortable and annoying sounds, to which attention should be paid in consideration of arresting exhaust sounds, are those at 600Hz and above. Attempts to arrest such high frequency sounds have included recourse to (1) absorption, (2) resonance (3) interference, and (4) filtration of the sound. In the practical application, however, a combination of the latter measures has been used for mufflers for exhaust gases. According to the prior art, sound-absorbing materials such as glass wool, steel wool and the like, are bonded to the inner surface of an exhaust passage within a muffler. However such techniques have failed to achieve an intended sound-absorbing purpose. According to another technique the direction of the exhaust gases is reversed to cause interference cancellation of sounds. In such case there tends to remain uncomfortable sounds of a high frequency as a result of the use of a hard impinging plate made of steel or the like.